react app

react-app/node_modules/react/lib/accumulateInto.js

@@ -0,0 +1,62 @@
+/**
+ * Copyright 2014-2015, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ *
+ * @providesModule accumulateInto
+ */
+
+'use strict';
+
+var invariant = require("./invariant");
+
+/**
+ *
+ * Accumulates items that must not be null or undefined into the first one. This
+ * is used to conserve memory by avoiding array allocations, and thus sacrifices
+ * API cleanness. Since `current` can be null before being passed in and not
+ * null after this function, make sure to assign it back to `current`:
+ *
+ * `a = accumulateInto(a, b);`
+ *
+ * This API should be sparingly used. Try `accumulate` for something cleaner.
+ *
+ * @return {*|array<*>} An accumulation of items.
+ */
+
+function accumulateInto(current, next) {
+  ("production" !== process.env.NODE_ENV ? invariant(
+    next != null,
+    'accumulateInto(...): Accumulated items must not be null or undefined.'
+  ) : invariant(next != null));
+  if (current == null) {
+    return next;
+  }
+
+  // Both are not empty. Warning: Never call x.concat(y) when you are not
+  // certain that x is an Array (x could be a string with concat method).
+  var currentIsArray = Array.isArray(current);
+  var nextIsArray = Array.isArray(next);
+
+  if (currentIsArray && nextIsArray) {
+    current.push.apply(current, next);
+    return current;
+  }
+
+  if (currentIsArray) {
+    current.push(next);
+    return current;
+  }
+
+  if (nextIsArray) {
+    // A bit too dangerous to mutate `next`.
+    return [current].concat(next);
+  }
+
+  return [current, next];
+}
+
+module.exports = accumulateInto;